Fluid system pressure booster



Dec. 8, 1942. Y J. HUL MAN ETAL 2,304,096 I I FLUID SYSTEM PRESSURE BQOSTER I Filed Aug. 6, 1941 2 Sheets-Sheet 1 m zow W;

19431 J. HULMAN ETAL v 3041096 FLUID SYSTEM PRESSURE BOOSTER Filed Aug. 6, 1941 2 Sheets-Sheet 2 L/UL 10$ H04 5 PA/4FD Patented Dec. 8, 1942 rum) srsrnn PRESSURE. Boos'ma Y Julius Holman and BernardiBeaman,

. Dayton, Ohio Application August 6, 1941, Serial No. 405,673

1Claim. (01.123-1'74) (Granted under the. act of March 3, 1883; as

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment to us of any royalty thereon.

This invention relates to pressure boosters and is applicable to any fluid system wherein a fluid is moved against a resistance.

The resistance may-comprise no more than the friction encountered by the fluid in moving through the system, or it may include additional resistances, but in any event some pressure or head creating means is required at some part of the system to maintain flow. Whatever the form that such pressure creating instrumentality may take, there will be a difference in pressure, as between the upstream and downstream side thereof, in the system, suchdifference usually being greater as. the resistance to be overcome is higher.

Such pressure difierence is, of course, a function of a fluid system of this character, but there are many instances where the pressure drop on able, such for example as when the suction head, due to lift or equivalent frictional resistance, approaches the stage where a liquid cavitates at the suction side of a pump.

It is therefore an object of,this invention to provide means which may be incorporated in a fluid system of the general class above mentioned, and which will have the effect of raising the pressure at points where it may become undesirably low.

Another object is to provide a device of this kind which may be added to a conventional fluid system with little or no difficulty in installation.

Other objects and advantages and meritorious will become evident as the following de,

tailed description is read with reference to the drawings, wherein:

Figures 1 and 2 are diagrammatic illustrations" included only to facilitate description of the prinamended April 30, 1928; 370 0. G. 757) lfi measured upstream of the tank connection as at A-A; P2 the pressure within the pipe l0 measured at the tank connection as atB-B; P: the pressure within the tank l6; and P4 the pressure within the pipe l0 measured downstream of the tank connection asat CC.

In Figure 2, whichis a diagrammatic illustration of the apparatus Figure 1. but modified to illustrate the'subject matter of the invention, the same pipe l0, tank It, and conduit are used, the pressure P'i, P2, and PM being taken at the same sections, namely, A-A, BB and CC.

. the low side is so great as to be highly objection- The modification consists in removing a portion of the pipe in and replacing it with a venturi 24, i

the tank l6 being connected bythe conduit 20 into the throat of the venturi. Since the throat pressure P: and the tank pressure P: are still the same as they are in the arrangement Figur 1, the pressures P'1 and F4 will be higher, this being I an inherent function of venturi which is well understood.

The tank It may be assumed to be included in a fluid circulating system from which no part of the fluid is intentionally removedas an expansion tank in a cooling system, or, it may be so connected in a system as to bypassany part of the fluid from the high to the low pressure side of the system, or it may serve in both these capacities. The tank may also be used as a source of supply in a system from which fluid is gradually removed .and used, as, for instance, in a' fuel system for an internal combustion engine, or a combination of the several functions may be included in a single system.

In Figures 1 and 2 the tank I6 is shown as being vented to atmosphere through the opening 22 "but it will be obvious that this vent maybe connected to a source of pressure which may be above or below atmospheric pressure. I

Referring again to Figure 1, and assuming that there is no flow from the tank I 6 to the pipe I0, P2 is equal to Pa plus the head or equivalent head In Figure 1, which shows diagrammatically a connected to the pipe It! by a conduit 20. The.

tank may'preferably be vented at 22.

In Figure 1, P1 is the pressure within the pipe of the fluid above the pipe. A tank connection being necessary, it is made at the low pressure point in the system. If flow is in the direction of the arrow I4, P1 is greater than F: and P3 is greater than P4, the pressure loss being due to the flow of fluid in pipe Hi. If the'sections A-A and CC are at considerable distance apart,the pres- 'sure P4 maybe considerably less than P2.

This gradual pressure drop is a function of a system or this character, and'must'be compensatedfor,v if circulation is to continue, by some form of pressure raising means, usually a pump. Under some conditions of operation this presents no dimculty, being merely a matter of providing a pump'oi sufllcient capacity to raise the pressure the desired amount.

Under other circumstances, however, the operating characteristics of the pump are considerably affected by a low pressure P4 at the inlet side of the pump, as for instance when pumping a liquid and P4 falls so low that the liquid boils at the pump inlet.

Referring now to Fig. 2, P2 is equal to P3 plus the head, just as it is in Figure 1. Fluid flow through a venturi, however results in an increase in the velocity, and a consequent lowering of the pressure in the Venturi throat, the throat pres-. sure being always less than the pressure at points just before entering and after passingthrough the venturi. It follows that, isincethe throat pressure Pa is the same in Figure 2 as in Figure 1, the pressures P'i and P'4'in Figure 2 are respectively greater than the pressures P1 and P4 in Figure 1. Therefore by'connecting a tank and bottom of pipe 46. With theaddition oi the venturi as shown, the. pressure at the pump inlet feed pipe of a given pressure P: into the throat of a venturi 24, Figure 2, instead of directly into the pipe l0, Figure 1, all other points in'the system, Figure 2, have their pressures raised an amount corresponding to the diflerences between the pressures P1 and P4 of Figure l and P'i and F4 of Figure 2.

In applications in which there is no flow from the tank II into the pipe 10, 1: is equal to P3 plus whatever head is provided by the elevation of the liquid level in the tank above the pipe.

However, in an installation in, which fluid is diverted from the pipe iii of the system upstream of the tank connection and returned to the tank, flow will occur between the tank and pipe. This flow will naturally lower the pressure P2 somewhat, but the pressure decrement may be kept to a small value by using as large a pipe as practicable.

The foregoing description is intended to cover the improved pressure booster generally. However, with a view of more clearly describing the principles involved, and without intent to place any limitation on its application, several specific embodiments oi the invention hadpreferably be described. The exempliflcation appearing in Figure 3 relates to a cooling system for an internal combusw tion engine or its equivalent, and comprises an.

engine 28 having a cooling jacket 2| and a pump ill for circulating the coolant. Principal circulation is from pump 30 through pipe 32 through jacket 28, pipe 34- air cooled radiator 38, pipe 38, and venturi to the pump inlet 45.

Auxiliary circulation is from a high point in the main system through pipe 42expansion tank 44.

and pipe 40 to the throat 41 of the venturi. The expansion tank II is vented to the atmosphere at 48 so that the pressure at the Venturi throat is fixed by the height of the level of the coolant in the expansion tank above the Venturi throat.

Without the venturi, the pressure at the pump inlet '45 would be the same as the pressure-at the may be considerably higher than that at the bottom of pipe 46. The desirability of raising the pressure attheinlet side of the pump in a system of the kind is well understood.

While one specific embodiment of the invention has been shown and described, and its superiority-noted, it will be apparent that the invention may be employed to good advantage in substantially any circulating fluid system where it is desirable' to raise the pressure on the low pressure side of the circuit, which will be at the intake of the pressure producing means. This pressure rise is accomplished with little change in conventional include any connection near enough to the throat -side' of said radiator to the inlet side of. said.

to get-the benefit of the increased flow and lowered pressure.

We claim:

A cooling system for an engine, comprising a coolant jacket for said engine, a coolant pump, a pipe connecting the discharge side of the pump to the lower end of said jacket, -a radiator below said jacket, a pipe connecting the upper side of said jacket to theupper side or said vradiator, means containing a channel connecting the lower pump, said connecting means including aventuri,an expansion tank above said jacket, a conduit connecting the bottom ofsaid expansion tank to' the throat of the venturi, and a conduit connecting the upper side of said jacket to the upper side of said expansion tank.

JULIUS HULMAN. BERNARD BEAMAN. 

